The present invention relates generally to compounds, compositions and methods regulating the action and function of androgens and other steroid hormones by modulating the activity of steroid-reductases, including isozymes of xcex1-reductases.
In some of the androgen-sensitive organs, such as the prostate and skin, testosterone (T) is converted to a more active metabolite 5xcex1-dihydrotestosterone (DHT) by 5xcex1-reductase (Anderson and Liao, 1968; Bruchovsky and Wilson, 1968). Other substrates of 5xcex1-reductases are also converted to reduce products that may have specific properties. Inhibition of 5xcex1-reductase represents a unique approach for developing therapeutic methods for androgen-dependent diseases, such as benign prostatic hyperplasia, breast and prostatic cancer, skin disorders, seborrhea, common baldness, hirsutism, and hidradenitis suppurative. Various compounds have been shown to inhibit 5xcex1-reductase activity (Liang and Liao, 1992; Hirsch et al., 1993; Russell and Wilson, 1994; Liao and Hiipakka, 1995). Finasteride (Proscar), a 5xcex1-reductase inhibitor, lowers the level of DHT in serum and the prostate, reduces prostate volume and increases urinary flow in some patients (Stoner E. Finasteride Study Group, 1992). Certain aliphatic unsaturated fatty acids, such as xcex3-linolenic acid (Liang and Liao, 1992) and catechin-3-gallates (Liao and Hiipakka, 1995), can inhibit 5xcex1-reductase activity of liver and prostate of rats and humans in vitro.
5xcex1-Reductase is found in many organs (Russell and Wilson, 1994; Hiipakka et al., 1993) including the sebaceous gland of hamsters (Takayasu and Adachi, 1972) and human hair follicles (Randall, 1994). Two 5xcex1-reductase isozymes have been identified in rats and humans (Russell and Wilson, 1994). The type 1 isozyme predominates in rat tissues such as liver, kidney, brain, and lung, whereas the type 2 enzyme is more abundant in rat testis and epididymis. Both isozymes are found in skins of the neonate, but the type 1 isozyme is the major form expressed in the skin after puberty. The type 1 isozyme is also expressed in balding scalp. The possibility that the type 2 isozyme plays a unique role in skin and hair growth cannot be excluded. Finasteride, a 4-azasteroid, is a competitive inhibitor of 5xcex1-reductases and has an affinity 30-fold higher for isozyme 2 than for isozyme 1 (Russell and Wilson, 1994). In contrast, the green tea catechins, epicatechin-3gallate and epigallocatechin-3-gallate are more effective inhibitors of the type 1 enzyme and xcex3-linolenic acid inhibits both isozymes equally well (Liao and Hiipakka, 1995).
In the stumptail macaque, a monkey model of androgenic alopecia, finasteride given orally prevents frontal baldness (Diani et al, 1992). The paired hamster flank organs, one on each side of the costovertebral angle, are highly sensitive to androgen stimulation. Topical application of xcex3-linolenic acid suppresses only the androgen-dependent growth of the treated hamster flank organ without showing systemic effects on the contralateral flank organ and this effect is very likely due to local inhibition of 5xcex1-reductase.
Uses of androgens known to the medical arts include, for example, treatment of hypogonadism and anemia. The abuse of androgens among athletes to enhance performance is well known. Androgens are also known to promote the development of benign prostatic hyperplasia (BPH), prostate cancer, baldness, acne, obesity and undesirable lipid and steroid profiles in blood and organs. Approximately 70% of males in the U.S. over the age of 50 have pathological evidence of BPH. Prostate cancer is the second leading cause of cancer death in males in the U.S. Male-pattern baldness can start as early as the teens in genetically susceptible males, and it has been estimated to be present in 30% of Caucasian males at age 30, 40% of Caucasian males at age 40, and 50% of Caucasian males at age 50. Further, acne is the most common skin disorder treated by physicians. In women, hirsutism is one of the hallmarks of excessive androgen. The ovaries and the adrenal are the major sources of androgen in women.
In men, the major androgen circulating in the blood is testosterone. About 98% of the testosterone in blood is bound to serum proteins (high affinity binding to sex-steroid binding globulin and low affinity binding to albumin), with only 1-2% in free form. The albumin-bound testosterone, the binding of which is readily reversible, and the free form are considered to be bioavailable, and account for about 50% of total testosterone. Testosterone enters target cells apparently by diffusion. In the prostate, seminal vesicles, skin, and some other target organs, it is converted by a NADPH-dependent 5xcex1-reductase to a more active metabolite, 5xcex1-DHT. 5xcex1-DHT then binds an androgen receptor (AR) in target organs. The 5xcex1-DHT-receptor complexes interact with specific portions of the genome to regulate gene activities (Liao et al., 1989). Testosterone appears to bind to the same AR, but it has a lower affinity than 5xcex1-DHT. In tissues such as muscle and testes, where 5xcex1-reductase activity is low, testosterone may be the more active androgen.
The difference between testosterone and 5xcex1-DHT activity in different androgen-responsive tissues is further suggested by findings in patients with 5xcex1-reductase deficiency. Males with 5xcex1-reductase deficiency are born with female-like external genitalia. When they reach puberty, their plasma levels of testosterone are normal or slightly elevated. Their muscle growth accelerates, the penis enlarges, voice deepens, and libido toward females develops. However, their prostates remain non-palpable, they have reduced body hair, and they do not develop acne or baldness.
The findings in 5xcex1-reductase deficient patients suggest that inhibitors of 5xcex1-reductase would be useful for the treatment of prostatic cancer, BPH, acne, baldness, and female hirsutism. Clinical observations and animal experiments have indicated that spermatogenesis, maintenance of libido, sexual behavior, and feedback inhibition of gonadotropin secretion do not require the conversion of testosterone to 5xcex1-DHT. This is in contrast to other hormonal therapies which abolish the actions of both testosterone and 5xcex1-DHT.
Treatment of androgen-dependent skin and prostatic diseases by 5xcex1-reductase inhibitors would be expected to produce fewer side effects than the presently available hormonal therapies. These include castration, estrogen therapy, high doses of superactive gonadotropin-releasing hormone such as Luprolide, and the use of competitive antiandrogens which inhibit AR binding of testosterone and 5xcex1-DHT, such as flutamide, cyproterone acetate and spironolactone. The long term efficacy of competitive antiandrogens is also compromised by their block of the androgenic feedback inhibition of gonadotropin secretion. This increases testicular secretion of testosterone. The higher level of testosterone eventually overcomes the action of the antiandrogen.
Excessive 5xcex1-DHT is implicated in certain androgen-dependent pathological conditions including BPH, acne, male-pattern baldness, and female idiopathic hirsutism. It has been shown that 5xcex1-reductase activity is reported to be higher in hair follicles from the scalp of balding men than that of non-balding men.
Since normal or slightly elevated plasma levels of testosterone in 5xcex1-reductase deficient males produce beneficial effects, it is desirable to provide agents that inhibit particular androgen action while maintaining normal testosterone levels.
The present invention relates to pharmaceutical compositions and methods for treating androgen related disorders. The pharmaceutical compositions may include a 5xcex1-reductase inhibitor, such as natural and synthetic flavanoids, catechols, curcumin-related substances, quinones, catechins, particularly epigallocatechin derivatives, fatty acids, and the salts, esters, analogues, pro-drugs, isomers, racemic mixtures, or derivatives of any of the foregoing. The inventive compositions may alternatively comprise mixtures of more than one 5xcex1-reductase inhibitor. In certain aspects, these compounds are employed to repress androgenic activity by inhibiting the formation and availability of active androgen in target cells. Consequently, the present invention is useful for the treatment of a wide variety of conditions including, but not limited to, the treatment of prostatic hyperplasia, prostatic cancer, breast cancer, skin cancer and other skin diseases, hirsutism, male pattern baldness, seborrhea, obesity, and other diseases related to lipid synthesis, body weight, and/or androgen function. Several of these compounds have been shown to effectively decrease body weight, and in some cases, to decrease the weight of an androgen-dependent body organ, such as the prostate and other organs. The effectiveness of these compounds may be dependent also on their action on other mechanisms involved in angiogenesis, cellxe2x80x94cell interaction, and on their interaction with various components of organs and cells.
Compounds useful in the practice of the present invention include various isomers of saturated and unsaturated fatty acids, their natural and synthetic analogues and derivatives from which these fatty acids can be generated as well as the metabolites and oxidation products of these fatty acids. The use of these and other fatty acids and their derivatives is also contemplated. Also useful are catechin compounds, particularly, catechins that are structurally similar to epicatechin gallate (ECG) and epigallocatechin gallate (EGCG). EGCG has an additional hydroxyl group compared to the epicatechin gallate molecule, which has been found to be surprisingly active in modulating several 5xcex1-reductase mediated processes. EGCG derivatives having such an additional OH group were shown to be active in inducing body weight loss and particularly in reducing the size of androgen sensitive organs such as preputial glands, ventral prostate, dorsolateral prostate, coagulating glands, seminal vesicles, human prostate tumors, and breast tumors in nude mice.
In more particular aspects of the invention, the inventors have discovered that certain catechins, particularly EGCG, can be administered to promote body weight loss that differentially affects overall body weight and prostate weight loss. In particular examples, it was shown that for a certain percentage of overall body weight loss, prostate weight loss was percentage-wise more than three times as much. The loss in body weight and the organ weight are likely due to EGCG interference of a common step in the pathway controlling body weight and the organ weight gain. EGCG and related compounds may interact and interfere with a receptor macromolecule (probably containing a protein) that modulates specific lipid synthesis and accumulation. Lipids can modulate gene expression, cell development and differentiation, and organ growth. Specific interference of lipid metabolism in the cells and organs may control the growth of the organs, in particular, prostate, sebaceous, preputial and other secretory organs. In certain applications, it is expected that benign or abnormal growth or cancer of these organs may be treated or even prevented by administration of catechin related compounds.
It has been demonstrated that catechin compounds will arrest or reduce human prostate and breast cancer cell growth. The effectiveness of catechin compounds was shown to be dependent on the methods by which these compounds were administered to the experimental animals. Intraperitoneal application was much more effective than oral administration. It is expected that direct application to the organs, such as the prostate, will be very effective. EGCG was surprisingly effective in suppressing and even reducing the size of human prostate and breast tumors in animal models. The effect was illustrated with EGCG; however, structurally similar catechin compounds are also effective, particularly those that are structurally similar to EGCG in having at least one additional hydroxyl group as compared with ECG. Thus, the EGCG species that contains eight hydroxyl groups is significantly more effective in reducing body weight than is ECG, which contains seven hydroxyl groups. Compounds of this general structure are expected to be particularly effective in chemoprevention and chemotherapy of human prostate cancer. Compounds having a structure similar to a part of structure of EGCG are also expected to be effective.
Compounds can be used as antiandrogenic agents through topical or systemic application. A preparation for this purpose can include a carrier, a protectant, an antioxidant (such as vitamin C or E, and various catechins and polyphenols), and other pharmaceutical and pharmacological agents. It is also expected that such compounds can be used in a delivery system (oral, local application, injection, or implantation) involving molecular recognition through which the compounds are delivered to target sites. Such a delivery system may involve, among other methods, liposome techniques or immunological devices.
The present invention also relates to novel compounds. These compounds have the formula: 
where x is xe2x80x94NHCH2CH2xe2x80x94 or xe2x80x94CHxe2x95x90CHxe2x80x94;
R1, R2 and R3 each may be xe2x80x94H, xe2x80x94OH or xe2x80x94OCH3, provided that only one of R1,R2, and R3 may be xe2x80x94H;
R4, R5 and R6 each may be xe2x80x94H, xe2x80x94OH, xe2x80x94OCH3 or xe2x80x94N(CH3)2, provided that only one of R4, R5 and R6 may be xe2x80x94H; and
n is 0 or 1.
Further, the epigallocatechin derivatives may have the formula: 
The use of testosterone (or DHT) combinations with the aforementioned 5xcex1-reductase inhibitor compounds are also contemplated. The disclosed 5xcex1-reductase inhibitor compounds may be administered in combination with a therapeutically effective amount of testosterone (or DHT) in a pharmaceutically acceptable carrier in the treatment of the various disorders. In one embodiment, the pharmaceutical composition is a percutaneous dosage form comprising testosterone and EGCG.